Bulk delivery of crosslinkable aqueous slurry explosive with crosslinking agent in a separate feed



g- 1970 R. B. HOPLER, JR ,5 8

BULK DELIVERY OF CROSSLINKABLE AQUEOUS SLURRY EXPLOSIVE WITHCHOSSLINKING AGENT IN A SEPARATE FEED Filed Nov. 16, 1967 ALTERNATE AIRROBERT B. HOPLER, JR.

INVENTOR.

v,7 BY

United States Patent Int. Cl. C06]: 1/00 US. Cl. 149-109 10 ClaimsABSTRACT OF THE DISCLOSURE A method for bulk delivery of an aqueousslurry blasting agent to the packaging unit of an explosive plant orinto the borehole of a blasting operation by pumping through a conduit.A suspension is injected into a moving stream of pumpable aqueous slurryblasting mixture containing guar gum under controlled conditions of pHwhereby the end product emerging from the conduit is crosslinked to adesired degree of firmness.

This application is a continuation-in-part of my copending applicationSer. No. 661,250, filed Aug. 17, 1967, now abandoned, which is acontinuation of my application Ser. No. 528,527, filed Feb. 18, 1966,now abandoned', which was a continuation of my application Ser. No.386,317, filed July 30, 1964, now abandoned.

This invention relates to aqueous slurry blasting agents andparticularly to a method for the bulk delivery of crosslinked aqueousslurry blasting agents.

The use of aqueous slurry blasting agents has become widespread inrecent years due to the relatively low cost of the ingredients involved.Additionally, it has been common practice to bulk load boreholes orcontainers with slurry blasting agents by gravity flow, air pressure,water pressure of similar means; here again, in quest of utmost economy.However, more recently the art has converted to gelled and crosslinkedaqueous slurry blasting agents particularly in view of their superior insitu properties in respect to water resistance, plasticity andcohesiveness. These crosslinked blasting agents are of firm body'andtend to hold their shape but, nevertheless, undergo sufficient innateplastic flow to completely fill a borehole or container. Additionally,the extent of plastic flow which these slurries exhibit is generallysuch that the slurry will not run out of the borehole into seams, cracksor crevices and will not lose its integrity in the presence of copiousamounts of water. Aqueous slurry blasting agents of this type and theirmethod of manufacture are well known in the art.

From the foregoing, it will be appreciated that the firm body impartedto the crosslinked slurry blasting agents mitigates their use for bulkdelivery systems, which sys tems are highly desirable from an economicstandpoint in respect to filling boreholes and containers. For example,one of the most satisfactory systems for loading boreholes or containersis by pumping, and the crosslinked aqueous slurry blasting agents asheretofore known and utilized are not entirely suitable for this. Forexample, the many industrial gums classified of polysac- 3,523,048Patented Aug. 4, 1970 F Ice charides or their derivatives when disperesdin water swell to produce gels, highly viscous dispersions, orsolutions. These gums by virtue of their hydratable nature give adelayed action thickening effect and when employed for the purpose ofpreventing settling out of particulate material in aqueous slurryblasting agents have been found reasonably satisfactory. On the otherhand, however, it has been found that the crosslinked gums are quitesuperior due to their ability to impart higher viscosity to dispersionsat lower concentrations and to be fast acting. It is in this latterclass of gums to which applicants copending application is directed andthe present invention.

Moreover, it Will be appreciated that in using hydratable gums as adelayed action thickening agent or in using crosslinkable gums, that ifthese gums are initially incorporated into the blasting agent for bulkdelivery and some unforeseen exigency arises at the blasting site todelay placement of the bulk blasting agent, that a mass of unpumpableblasting agent may readily be at hand. Furthermore, since it is commonpractice in some instances of bulk delivery to use mix trucks and tofeed together simultaneously all materials at the blasting site whichwhen combined form the aqueous slurry blasting agent, an undesirablecondition exists if a prolonged delay occurs.

The method of my copending application, heretofore identified,eliminates the foregoing deficiencies by providing a secondary streamfor injection of crosslinking guar gum into a primary moving stream ofthe blasting agent ingredients. By using this injection technique, theblasting ingredients may be mixed at a plant and hauled to the blastingsite or they may be mixed at the blasting site and if any unforeseenexigency arises, the secondary injection stream is simply turned down orolf or ingredient controlled until normal operations are resumed. Theobjects of the present invention, therefore, are similar to those of mycopending application with additional objects and advantages includingaeration being set forth as will appear hereinafter, the novel featuresand combinations being set forth in the appended claims.

Generally described, the present invention contemplates a method forbulk delivery of a crosslinked aqueous slurry blasting agent in whichthe improvement comprises forming a moving stream of pumpable aqueousslurry blasting mixture of the inorganic oxidizer salt type having thediscrete ingredients thereof held in suspension or dispersion by thethickening action of a crosslinkable guar gum, forming a moving streamof pumpable injection mixture essentially containing sufficientcrosslinking agent to crosslink the crosslinkable guar gum andeffectively impart firmness to the aqueous slurry blasting mixture,injecting the moving stream of pumpable injection mixture into themoving stream of pumpable aqueous slurry blasting mixture, and pumpingthe entire intimate mixture thus formed at a pH of less than 6 throughan elongated conduit to effect bulk delivery thereof at a rate of timewithin said conduit to obtain substantial crosslinking and firmness ofthe intimate mixture upon discharge from the said conduit.

As a preferred embodiment, the invention contemplates a method for bulkdelivery of a crosslinked aqueous slurry blasting agent into a borehole,of a blasting operation in which the improvement comprises pumping aprimary stream of aqueous slurry blasting mixture of the inorganicoxidizer salt type from a slurry mixture pump through a hose directlyinto a borehole, said mixture having the discrete ingredients thereofheld in suspension or dispersion by the thickening action of acrosslinkable guar gum, and pumping a secondary stream essentiallycontaining sufficient crosslinking agent to crosslink the crosslinkableguar gum at a pH of less than 6 into the primary stream of aqueousslurry blasting mixture and passing the mixture thus formed through thehose to obtain substantial crosslinking and firmness of said mixture bythe time it discharges from said hose.

The preferred embodiment of the invention chosen for purposes ofillustration and description is shown in the accompanying drawing whichis a diagrammatic plan view of an arrangement of apparatus for carryingthe invention into effect for the loading of boreholes in the field.

In the drawing an air-driven motor 10 drives a first Moyno pump 12 byengagement of a motor pulley 14 with a first pump pulley 16 through abelt 18. The airdriven motor 10 also drives a second Moyno pump 20 byengagement of a second pump pulley 22 with a clutch pulley combination24 through a belt 26. Pump pulleys 16 and 22 are secured to the driveshaft of Moyno pump 12 and pump pulley 24 is affixed to the drive shaftof Moyno pump 20 with the clutch engagement thereof variably controlledby lever arm 28.

An example of operation of this apparatus and the method of theinvention follow. A pumpable aqueous slurry blasting mixture containingcrosslinkable guar gum from a mix truck, a tank delivery truck or othersuitable supply source (not shown is passed through line into the firstMoyno pump 12. Simultaneously therewith, a pumpable injection mixturecontaining crosslinking agent to crosslink the crosslinkable guar gumfrom a compartment of a mix truck, a tank delivery truck or othersuitable supply source (not shown) is fed through line 32 into thesecond Moyno pump 20 and pumped therefrom through line 34 into the firstMoyno pump 12. The slurry mixture from line 30 and the injection mixturefrom line 34 are thus intimately mixed in Moyno pump 12 and pumpedtherefrom into a conduit or hose 36 and therefrom into a borehole (notshown). Alternatively, the injection mixture from line 34 may be pumpeddirectly through line 38 into the moving stream passing through theconduit 36. Intimate mixing is obtained, likewise, with thisarrangement. Control valves, check valves, gages, pressure tanks, andthe like have not been illustrated since the provision and operation ofsuch auxiliary equipment are commonly understood.

It will be appreciated as generally described that the blasting mixturemay be formulated having all ingredients per se non-explosive as well asformulated having certain ingredients explosive.

The following table presents typical primary pumpable aqueous slurryblasting mixtures and typical secondary pumpable injection mixtures forutilization in accordance with the present invention.

TABLE I Pumpable Aqueous Slurry BlastingMixture Percent by weightExample 1 2 3 4 Ingredients:

Water 16. 5 17. 0 16. 5 16. 5 Smokeless Powder (ground) 32. 5 30. 4Ammonium Nitrate (prills) 38. 7 32.5 52. 0 53.0 Sodium Nitrate (prills)10. 0 10. 0 15. 6 15. 6 Aluminium (all thru 20 mesh s v 7. 8 8. 5Silicon (all thru 80 mesh sieve) 8. 5 Coal (ground) 1. 2 1. 2 Glycol 1.5 1. 5 5.0 5. 0 Guar Gum (crosslinkable) 0.7 0.67 1.0 1.0 Fumarie Acid 10. 05 0. 08 Pine Oil 0.05 0.05

Total 100 00 100. 00 100. 00 100. 00

Pumpable InjeetionMixture Percent by weight Example A B Ingredients:

Potassium pyroautimouatc (DWG) (crosslinking agent) 14. 0 Fumaric Acid 1Added together as one component. 2 Add acid to adjust pH from about 3.0to about 5.0. 3 Added together as other component.

Various combinations of the blasting and injection mixtures given inTable I were field tested by pumping into boreholes at rates varyingfrom about 200 to about 600 pounds per minute and were foundsatisfactory in all respects when shot with conventional boosters. Forexample, injection mixture A was fed through line 32 into Moyno pump 20and was pumped therefrom through line 38 directly into the stream ofblasting mixture of Example 1 being pumped from Moyno pump 12 and passedthrough conduit 36. In like manner, injection mixture A was rimar abl 1Int 1 cr ofdififaui 23.1511 ;wfliiiitfisfiiifiiiefifig Pumped Stream ofblastmg were OtEXamPIe agent to hold the discrete ingredients in themixture in 2 and Injectlon mixture B was fed through km 32 suspension ordispersion for an indefinite period of time, puml? 20 and was pumpedthefefmnf through hue when desired or necessary, without any deleteriousef- 38 directly. Into the stream of blastmg mlxture of EX- fect. Suchdiscrete ingredients may include, for example, ample 1 bemg Pumped fMoyno p? and Bassed undissolved inorganic oxidizer salt, such as,ammonium through condmt.36' In hke r f Imxture nitrate, sodium nitrate,ammonium and sodium perchlo- B was pumped Into the stream of blasnngmlxmre of rates; nonexplosive fuels, such as, particulate fuel or im-Examples 3 and miscible liquid fuel which must be suspended or dispersedThe of F 1 mlxture Pumped throughout the aqueous phase; solid materials,such as Into the Stream of primary blaslmg mlxture w In a solid DNT,coal, sulfur, gilsonite and liquid materials case P by Welght of hentire blfistmg Such as liquid DNT, saccharides, glycols, amine nitratescomposition. All products were substantially crosshnked formamide, urea;explosive materials, such as smokeless and firm upon dlscharge from thecondult or hose Into powder, nitrostarch, TNT, RDX, HBX, HMX, PETN, theboreholes. Table II, which follows, gives the pH Pentolite, Cyclotol;and metal energizers, such as, alumiand Specific gravity in respect tothe Various Combinations num, silicon, calcium silicide, calcium boride,silicon of blasting mixture and injection mixture set forth above.

TABLE II Combinations 1-A 2-A 3-A l-B 2-B 3-B 4-13 pH .-3.0-4.5 3.0-4.53.0-4.5 3.04.5 3.04.5 5.0 5.2 Maximum Specific Gravity 1. 4-1.51.4-1.5 1. 4-1.5 Aerated Specific Gravity 1.15 1.15 1.13 1.15

carbide, ferro silicon, magnesium, and alloys and mix- With reference tothe foregoing Table II, it will be tures thereof. Thus, the primarypumpable aqueous slurry appreciated that the blasting compositions 1-Band 2-B,

although containing explosive sensitizer, were increasingly sensitizedby aeration and that the blasting compositions 3-B and 4-B, althoughcontaining no explosive sensitizer, were likewise increasinglysensitized by aeration as evidenced more particularly by composition 4-Bcontaining silicon which is characteristic of some metals includingcertain types of aluminum which contribute little or nothing in respectto sensitization in the absence of aeration. The term an aeration agentas used herein means an agent which causes the composition to becombined with or charged with gas. The term maximum specific gravity asused herein means the specific gravity of the aqueous slurry blastingagent exclusive of gas, and the term aerated specific gravity as usedherein means the specific gravity of the aqueous slurry blasting agentinelusive of gas. It is recognized that evenly dispersed air or gasbubbles throughout an explosive can be beneficial to initiation andpropagation. Such gas bubbles may be generated as disclosed by Fergusonet al. (US. 3,288,- 658) and Swisstack (US. 3,288,661). A preferredaeration agent is sodium nitrite as shown in Table I, Example B.Regardless of the aeration agent chosen, it may simply be incorporatedin the injection mixture. This, of course, permits holding the volume ofthe primary or base blasting mixture to a minimum in the mixing chamberof a mix truck or in the tank of a delivery truck. And this isparticularly advantageous when using a fast gas generating material suchas sodium bicarbonate, or a mixture such as sodium bicarbonate andsodium nitrite, or air.

Various blasting ingredients which may be utilized in accordance withthe present invention have heretofore been set forth with preferredblasting mixtures and injection mixtures being presented in Table 1.Generally, however, the various ingredients will be employedapproximately as follows.

The inorganic oxidizing salts are shown in the examples as being presentin amount of 48-68% of the compositions. If requirements so dictate,these salts could comprise between 30 and 75% of the compositions. Thephysical form of the salts is not critical, coarse or fine, or mixturesof coarse and fine prilled and/or granular to powdery material all beingsuitable. lln fact, in some preferred applications, the oxidizing saltsare introduced into the compositions as an aqueous solution. Ammoniumnitrate (AN), because of its availability, is the preferred oxidizingsalt but sodium nitrate (SN) in practice almost always makes up aportion of the oxidizing salts, preferably to the extent of about 5% to25% of the composition, but 0% to about 30% may be used. Although theexamples given are all formulated with inorganic nitrates, the use ofother inorganic oxidizing salts are within the scope of this invention.For instance, various of the alkali or alkaline earth nitrates may beused for all or a portion of the AN, but in practice, not more than 80%of the AN would be so substituted. A preferred range for the presence ofAN is from about 30% to about 75%. In addition, salts selected from theperchlorates and less desirably, the chlorates in the absence ofammonium nitrate may be used. Examples of these are the ammonium, sodiumand potassium salts with ammonium and sodium perchlorates beingespecially advantageous.

The nonexplosive carbonaceous fuels appear in the examples as beingpresent in amount of 1-6% of the compositions. Depending upon theconditions, 3% to 15% of the compositions may be made up of one or morecarbonaceous fuels, but 3% to 12% is more commonly used. The nature ofthe carbonaceous material is not ordinarily critical but at lowerlevels, soluble fuels, amine nitrates, glycols, such as ethylene glycoland saccharides, such as ordinary granulated sugar, are preferred. Whereinsoluble particulate carbonaceous fuel or immiscible carbonaceousliquid fuels are used, they must, of course, be suspended in ordispersed throughout the aqueous phase.

Water is shown as 16-17% by weight of the compositions in the examples.Between 10 and 30% of the compositions may be composed of water but inconventional practice 14 to 24% is more commonly employed.

It will be appreciated that the compositions of this invention may becomposed of a blend of liquid and solid components. It is essential thatthe solid phase or nonhomogeneous liquid phase, when such is utilized,be uniformly dispersed throughout the liquid phase. Solid materials,such as DNT, coal, sulfur, gilsonite and the like, and the liquidmaterials such as DNT, nitroparafiins, fuel oil and the like may be soutilized. This is accomplished by employing thickening agents, such ascrosslinkable guar gum, which retard or arrest the separation of thesolid and liquid materials and yet retain the primary mixture pumpable.Preferred practice is to employ noninhibited, hydratable, guar gum inthe primary mixture and to crosslink (gel) the gum With a suitablecrosslinking agent. The crosslinking agent may be combined with the gumas disclosed in my copending application and is commercially availablein such form as the in hibited, self-complexing or the non-inhibited,self-complexing type or it may be added as a separate ingredient in verysmall amounts, usually less than 0.1% of the total composition. The gummay be used in as low amount as 0.4% or thereabouts and up to about 4%,but more generally from about 0.7% to about 1.8% is used having aparticle size so that substantially all passes through a 60 mesh sieve.Potassium pyroantimonate at the pH as used in the examples is apreferred crosslinking agent but other crosslinking agents may be used,such as, potassium dichromate, sodium dichromate, and mixtures ofantimony sulfides and oxides with alkali metal chromates anddichromates.

The explosive sensitizers, when used, may be pelleted, flaked, grained,ground or liquid as desired and present in an amount of from about 10 toabout 40% by weight of the total composition.

The metal energizers, when used, are in particulate form and present inan amount of from about 3 to about 30% by weight of the totalcomposition.

The pH of the composition can be adjusted with acid or base as required.For this purpose, fumaric acid has been demonstrated, but other acidsand buffer salts may be used, such as, acetic acid, citric acid, nitricacid, sulfonic acid, hydrochloric acid, and soda ash, and the like. A pHof less than 6.0 is mandatory, and less than 5.0 is preferred for thefinal composition.

In using the improved technique of this invention in the field, pumpingrates of from about 200 to about 1000 pounds per minute are feasible forplacing blasting composition into boreholes. When placing blastingcomposition into packages at a plant site or a blasting site, the rateof pumping is, of course, adjusted to accommodate the desired rate ofpackage production.

From the foregoing, it will be apparent that the advantages of theinvention have been demonstrated giving the art a flexibility in thehandling, delivery and placing of finished crosslinked aqueous slurryblasting agents which heretofore has not been available.

What I claim and desire to protect by Letters Patent 1. A method forbulk delivery of a crosslinked aqueous slurry blasting agent in whichthe improvement comprises (a) forming a moving stream of pumpableaqueous slurry blasting mixture of the inorganic oxidizer salt typehaving the discrete ingredients thereof held in suspension or dispersionby the thickening action of a crosslinkable guar gum,

(b) forming a moving stream of pumpable injection mixture essentiallycontaining sufiicient crosslinking agent to crosslink the crosslinkableguar gum and effectively impart firmness to the aqueous slurry blastingmixture,

(c) injecting the moving streamof pumpable injection mixture into themoving stream of pumpable aqueous slurry blasting mixture, and

(d) pumping the entire intimate mixture thus formed at a pH of less than6 through an elongated conduit to effect bulk delivery thereof at a rateof time Within said conduit to obtain substantial crosslinking andfirmness of the intimate mixture upon discharge from the said conduit.

2. The improvement according to claim 1 in which (a) the injectionmixture is injected into the moving stream of pumpable aqueous slurryblasting mixture by pumping the injection mixture thereinto.

3. The improvement according to claim 1 in which (a) the aqueous slurryblasting mixture is pumped to form the moving stream, and

(b) the injection mixture is injected into said moving stream by pumpingsaid injection mixture thereinto.

4. A method for bulk delivery of a crosslinked aqueous slurry blastingagent into a borehole of a blasting operation in which the improvementcomprises (a) pumping a primary stream of aqueous slurry blast ingmixture of the inorganic oxidizer salt type from a slurry mixture pumpthrough a hose directly into a borehole, said mixture having thediscrete ingredients thereof held in suspension or dispersion by thethickening action of a crosslinkable guar gum, and

(b) pumping a secondary stream essentially containing suflicientcrosslinking agent to crosslink the crosslinkable guar gum at a pH ofless than 6 into the primary stream of aqueous slurry blasting mixtureand passing the mixture thus formed through the hose to obtainsubstantial crosslinking and firmness of said mixture by the time itdischarges from said hose.

5. The improvement according to claim 4 in which (a) the secondarystream is pumped directly into the slurry mixture pump.

6. The improvement according to claim 4 in which (a) the secondarystream is pumped directly into the primary stream of aqueous slurryblasting mixture being passed into the hose.

7. A method for bulk delivery of a cross-linked aqueous slurry blastingagent in which the improvement comprises:

(a) forming a moving stream of pumpable aqueous slurry blasting mixtureof the inorganic oxidizer salt type having the discrete ingredientsthereof held in suspension or dispersion by the thickening action of acrosslinkable guar gum,

(b) forming a moving stream of pumpable injection mixture containing anaeration agent and essentially containing sufiicient crosslinking agentto crosslink the crosslinkable guar gum and effectively impart firmnessto the aqueous slurry blasting mixture,

() pumping the moving stream of pumpable injection mixture into themoving stream of pumpable aqueous slurry blasting mixture, and

(d) pumping the entire intimate mixture thus formed at a pH of less than6 through an elongated conduit to effect bulk delivery thereof at a rateof time within said conduit to obtain substantial crosslinking andfirmness of the intimate mixture upon discharge from the said conduit.

8. A method for bulk delivery of a crosslinked aqueous 10 to effect bulkdelivery thereof at a rate of time Within said conduit to obtainsubstantial crosslinking and firmness of the intimate mixture upondischarge from the said conduit.

9. A method for bulk delivery of a crosslinked aqueous slurry blastingagent into a borehole of a blasting operation in which the, improvementcomprises:

(a) pumping a primary stream of aqueous slurry blasting mixture of theinorganic oxidizer salt type from a slurry mixture pump through a hosedirectly into a borehole, said mixture having the discrete ingredientsthereof held in suspension or dispersion by the thickening action of acrosslinkable guar gum, and

(b) pumping a secondary stream containing an aeration agent andessentially containing sufficient crosslinking agent to crosslink thecrosslinkable guar gum at a pH of less than 6 directly into the primarystream of aqueous slurry blasting mixture in the slurry mixture pump andpassing the mixture thus formed through the hose to obtain substantialcrosslinking and firmness of said mixture by the time it discharges fromsaid hose.

10. A method for bulk delivery of a crosslinked aqueous slurry blastingagent into a borehole of a blasting operation in which the improvementcomprises:

(a) pumping a primary stream of aqueous slurry blasting mixture of theinorganic oxidizer salt type from a slurry mixture pump through a hosedirectly into a borehole, said mixture having the discrete ingredientsthereof held in suspension or dispersion by the thickening action of acrosslinkable guar gum, and

(b) pumping a secondary stream containing an aeration agent andessentially containing sufiicient crosslinking agent to crosslink thecrosslinkable guar gum at a pH of less than 6 directly into the primarystream of aqueous slurry blasting mixture being passed into the hose andpassing the mixture thus formed through the hose to obtain substantialcrosslinking and firmness of said mixture by the time it discharges fromsaid hose.

References Cited UNITED STATES PATENTS BENJAMIN R. PADGETT, PrimaryExaminer slurry blasting agent in which the improvement comprises:

(a) pumping a moving stream of pumpable aqueous slurry blasting mixtureof the inorganic oxidizer salt type having the discrete ingredientsthereof held in suspension or dispersion by the. thickening action of acrosslinkable guar gum,

S. J. LEOHERT, 1a., Assistant Examiner US. Cl. X.R.

Patent No.

Inventofl) UNITED STATES PATENT OFFICE Robert B. Hopler. Jr.

Dated August 4,4970

Itis certified that error appears in the above identified patent andthat said Letters Patentare hereby corrected as shown below:

Column 4,

In Table I under Example 4; 53.0 should read 52.0

AlSO in Table I, after line 30, Sodium nltrate should read Sodiumnitrite Amt:

I: :w comissiom 2 I u? arm UNITED STATES PATENT OFFICE Po-1o'5o (s/es)CERTIFICATE OF CORRECTION Patent No. 3 523, 048 Dated August 4 L970Inventor(s) Robert B. Hopler, Jr.

It is certified that error appears in the above-identified patent andthat said Letters Patent are hereby corrected as shown below:

" Sodium nltrate mm 1. mm, common at an Column 4, In Table I underExample 4,

should read 52.0

AlSO in Table I, after line 30,

should read Sodium nitrite on Elihu 51 film I 3m sdifiimlmmwwmww Afloat:

Edward M mum, Ii. Meeting Officer

